Several types of casting processes, including expendable mold casting and non-expendable mold casting, are categorized by the type of mold used, for example sand or metal molds. Further categorization varies by the method used to deliver molten metal to the mold.
In these various types of casting processes, it is common for cast objects to be formed from aluminum metal to decrease the overall weight of the object. Problems may arise from using aluminum metal for casting due to the fact that the volume of aluminum is reduced as it transitions from a liquid state to a solid state, i.e. as it cools to form a cast object. These problems can stem from the design of the mold and/or the process used for solidifying molten metal in the mold.